Lille broke the deadlock in the 86th minute when top scorer Moussa Sow's rising shot hit the crossbar and struck home goalkeeper Nicolas Penneteau on the back before bouncing over the line for an own goal.
Victory would have taken Rudi Garcia's men up to sixth, but barely a minute later Valenciennes drew level as Lille goalkeeper Mickael Landreau let a free-kick spring from his hands and Gregory Pujol slid in to volley home.
Sow could even have won the game in injury time, but his gentle header came back off the left-hand post with the advancing Penneteau beaten.
Lille, who finished fourth last season, climb to eighth in the table, while Valenciennes leap five places to 11th.
The Marseille-Rennes match, originally scheduled to take place on Saturday evening, was initially postponed until 1700 local time (1600GMT) on Sunday, but a pitch inspection on Sunday afternoon found that the Stade Velodrome pitch was still waterlogged.
"In the interests of precaution, the safety of the players is of primary importance," said match referee Fredy Fautrel.
With torrential rain widespread across southern France, Monaco's home game with Bordeaux was also called off after the Stade Louis II pitch was deemed unplayable.
Rennes went into the weekend with a one-point lead over Marseille at the top of Ligue 1, but Brest's 2-0 victory at home to Saint-Etienne on Saturday allowed them to go two points clear at the top of the standings.
Brest, promoted from the second division last season, are now guaranteed to remain on top of the standings until next weekend's fixtures.
"This is a great surprise," said Brest coach Alex Dupont.
"But the position we're in isn't down to luck. We're on the right track and deserved this victory."
Montpellier squandered the chance to move four places up to second after they were held to a draw by visiting Paris Saint-Germain in Sunday's late game.
PSG forward Ludovic Giuly opened the scoring shortly before half time; however, Montpellier were back on level terms five minutes later thanks to Marco Estrada.
It left Montpellier in sixth spot, still one place and two points better off than PSG.
In Saturday's other matches, Toulouse held onto fifth place after drawing 1-1 at home to third-bottom Lens, while Lyon reacted to their League Cup defeat at home to PSG by beating Sochaux 2-1.
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Victory would have taken Rudi Garcia's men up to sixth, but barely a minute later Valenciennes drew level as Lille goalkeeper Mickael Landreau let a free-kick spring from his hands and Gregory Pujol slid in to volley home.
Sow could even have won the game in injury time, but his gentle header came back off the left-hand post with the advancing Penneteau beaten.
Lille, who finished fourth last season, climb to eighth in the table, while Valenciennes leap five places to 11th.
The Marseille-Rennes match, originally scheduled to take place on Saturday evening, was initially postponed until 1700 local time (1600GMT) on Sunday, but a pitch inspection on Sunday afternoon found that the Stade Velodrome pitch was still waterlogged.
"In the interests of precaution, the safety of the players is of primary importance," said match referee Fredy Fautrel.
With torrential rain widespread across southern France, Monaco's home game with Bordeaux was also called off after the Stade Louis II pitch was deemed unplayable.
Rennes went into the weekend with a one-point lead over Marseille at the top of Ligue 1, but Brest's 2-0 victory at home to Saint-Etienne on Saturday allowed them to go two points clear at the top of the standings.
Brest, promoted from the second division last season, are now guaranteed to remain on top of the standings until next weekend's fixtures.
"This is a great surprise," said Brest coach Alex Dupont.
"But the position we're in isn't down to luck. We're on the right track and deserved this victory."
Montpellier squandered the chance to move four places up to second after they were held to a draw by visiting Paris Saint-Germain in Sunday's late game.
PSG forward Ludovic Giuly opened the scoring shortly before half time; however, Montpellier were back on level terms five minutes later thanks to Marco Estrada.
It left Montpellier in sixth spot, still one place and two points better off than PSG.
In Saturday's other matches, Toulouse held onto fifth place after drawing 1-1 at home to third-bottom Lens, while Lyon reacted to their League Cup defeat at home to PSG by beating Sochaux 2-1.
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